head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Practiced Mastery
An arcade FPS that scores you for killing enemies in the most creative ways possible.

Execution · Practiced Mastery
First-person parkour against zombies, especially terrifying after dark.
Bulletstorm leans Execution (Practiced Mastery); Dying Light leans Execution (Practiced Mastery).
Bulletstorm leans a little harder on execution, though the gap is small.
Bulletstorm
Leash, kick, and shot timing drive skillshot chains
Dying Light
Parkour traversal and melee timing demanding.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Bulletstorm
Enemies are scripted fodder for your combos
Dying Light
Zombie AI scripted, non-adaptive.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Bulletstorm
Arenas and spawns are fixed and learnable
Dying Light
Night-hunter encounters bring randomness.
Bulletstorm leans a little harder on optimization, though the gap is small.
Bulletstorm
Maximising skillshot score per arena is a solvable puzzle
Dying Light
Crafting, blueprints, skill trees solvable.
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.